Electronic substrate and electronic apparatus

ABSTRACT

Provided is an electronic substrate that achieves a reduction in a size of a substrate and enables a void risk in an underfill to be reduced, and an electronic apparatus. The electronic substrate in one aspect of the present technology includes an electronic chip that is placed above the substrate, an electrode that exists between the substrate and the electronic chip and electrically connects the substrate and the electronic chip, the underfill with which a space between the substrate and the electronic chip is filled so that the electrode is sealed and protected, a protection target to be protected from inflow of the underfill, the protection target being formed on the substrate, and an underfill inflow prevention unit that is formed in the substrate so as to surround an entirety or a portion of the protection target.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Pat. ApplicationSerial No. 17/145,071 filed on Jan. 8, 2021, which is a continuation inpart application of U.S. Pat. Application Serial No. 16/330,963, filedon Mar. 6, 2019, now U.S. Pat. No. 10,910,289, which is a U.S. NationalPhase of International Patent Application No. PCT/JP2017/037968 filed onOct. 20, 2017, which claims the benefit of priority from Japanese PatentApplication No. JP 2016-206876 filed in the Japan Patent Office on Oct.21, 2016. Each of the above-referenced applications is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology relates to an electronic substrate and anelectronic apparatus, and in particular, to an electronic substrate andan electronic apparatus, in which a prescribed electronic chip ismounted above a substrate and a space between the substrate and theelectronic chip is filled with an underfill (liquid curable resin) sothat an electrode between the substrate and the electronic chip issealed and protected.

BACKGROUND ART

Conventionally, there is a technology in which a prescribed electronicchip is placed above a substrate that configures an electronic apparatusand a space between the substrate and the electronic chip is filled withan underfill so that an electrode between the substrate and theelectronic chip is sealed and protected.

Furthermore, a technology for forming a groove on a substrate has beenproposed as a structure that prevents a filled underfill fromunnecessarily spreading (see, for example, Patent Document 1).

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-87239

SUMMARY OF THE INVENTION Problems to Be Solved by the Invention

Meanwhile, in the technology proposed in Patent Document 1, aconfiguration is employed in which a groove that prevents an underfillfrom unnecessarily spreading is formed in the shape of a frame thatsurrounds a chip and the area of the chip is secured so as to increaseby the area of the groove.

The present technology has been made in view of the situation above, andthe present technology realizes a reduction in the size of a substrate,and also enables a void risk in an underfill to be reduced.

SOLUTIONS TO PROBLEMS

An electronic substrate in a first aspect of the present technologyincludes: an electronic chip that is placed above a substrate; anelectrode that exists between the substrate and the electronic chip andelectrically connects the substrate and the electronic chip; anunderfill with which a space between the substrate and the electronicchip is filled so that the electrode is sealed and protected; aprotection target to be protected from inflow of the underfill, theprotection target being formed on the substrate; and an underfill inflowprevention unit that is formed in the substrate so as to surround anentirety or a portion of the protection target.

The underfill inflow prevention unit can have a multiple structure.

The underfill inflow prevention unit can be a recessed groove.

The recessed groove can have an inclination angle of 60° to 90° withrespect to a surface of the substrate.

A depth/width of the recessed groove can range from 0.5 to 16000. Theunderfill inflow prevention unit can be a protruding wall.

The protection target can be a connection pad that is connected toexternal equipment.

The protection target can be a light-receiving layer, the electronicchip can be a semiconductor chip including a functional circuit, and theelectronic substrate can be a component of a solid-state image sensor.

The underfill inflow prevention unit can be formed in the substrate soas to surround all or some of one or a plurality of the protectiontargets.

An electronic apparatus in a second aspect of the present technology isan electronic apparatus in which an electronic substrate is employed.The electronic substrate includes: an electronic chip that is placedabove a substrate; an electrode that exists between the substrate andthe electronic chip and electrically connects the substrate and theelectronic chip; an underfill with which a space between the substrateand the electronic chip is filled so that the electrode is sealed andprotected; a protection target to be protected from inflow of theunderfill, the protection target being formed on the substrate; and anunderfill inflow prevention unit that is formed in the substrate so asto surround an entirety or a portion of the protection target.

In the first and second aspects of the present technology, the underfillis suppressed from flowing in the protection target by the underfillinflow prevention unit.

EFFECTS OF THE INVENTION

In the first and second aspects of the present technology, a reductionin the size of a substrate can be realized, and a void risk in anunderfill can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view illustrating an example of a configuration inwhich a groove is formed above a substrate.

FIG. 2 is a top view illustrating the example of a configuration inwhich a groove is formed above a substrate.

FIG. 3 is a top view illustrating an example of a configuration in acase where the technology described with reference to FIGS. 1 and 2 hasbeen applied to a substrate that configures a solid-state image sensor.

FIG. 4 is a top view illustrating a configuration example of a substrateof a solid-state image sensor to which the present technology has beenapplied.

FIG. 5 is a sectional view in a case where an inflow prevention unit isa recessed groove.

FIG. 6 is a sectional view in a case where the inflow prevention unit isa protruding wall.

FIG. 7 is a top view illustrating a first variation.

FIG. 8 is a top view illustrating a second variation.

FIG. 9 is a sectional view illustrating a third variation.

FIGS. 10A and 10B are diagrams explaining a first configuration exampleof a structure between an underfill and an optical layer.

FIGS. 11A and 11B are diagrams explaining a second configuration exampleof the structure between the underfill and the optical layer.

FIG. 12 is a diagram explaining a third configuration example of thestructure between the underfill and the optical layer.

FIG. 13 is a diagram explaining a fourth configuration example of thestructure between the underfill and the optical layer.

FIG. 14 is a block diagram illustrating an example of a roughconfiguration of a vehicle control system.

FIG. 15 is an explanatory drawing illustrating an example of theinstallation position of an outside-vehicle information detector and animaging unit.

MODE FOR CARRYING OUT THE INVENTION

A best mode for carrying out the present technology (hereinafterreferred to as an embodiment) will be described below in detail withreference to the drawings.

Configuration Example of Solid-State Image Sensor

First, the configuration of a solid-state image sensor that causes thenecessity of the present technology will be described with reference toFIGS. 1 to 3 , before a solid-state image sensor according to thepresent embodiment is described.

FIG. 1 is a sectional view illustrating an example of the configurationof a solid-state image sensor in which a groove is formed above asubstrate. FIG. 2 is a top view that corresponds to FIG. 1 .

As illustrated in FIG. 1 , an electronic chip 13 is placed above asubstrate 11, and a space between the substrate 11 and the electronicchip 13 is filled with an underfill 14 that seals electrodes 12 thatelectrically connect the substrate 11 and the electronic chip 13.Furthermore, in the substrate 11, a groove 15 is formed in the shape ofa frame that surrounds a position where the electronic chip 13 isplaced, as illustrated in FIG. 2 , and the groove 15 suppresses theunderfill 14 from spreading.

FIG. 3 is a top view illustrating an example of a configuration in acase where the technology described with reference to FIGS. 1 and 2 hasbeen applied to a substrate that configures a solid-state image sensor.

In FIG. 3 , an optical layer 21 that includes a photodetector such as aphotodiode (PD) is formed on a surface of a substrate 11 that includesSi or the like. Furthermore, connection pads 22 that are connected to awire or the like that transmits various signals to external equipmentare formed on the substrate 11. Moreover, an electronic chip 13 thatincludes a logic circuit or the like is placed above the substrate 11.

A space between the substrate 11 and the electronic chip 13 is filledwith an underfill 14 that seals electrodes 12 that electrically connectthe substrate 11 and the electronic chip 13. Furthermore, a groove 15 isformed in a frame shape around a position where the electronic chip 13is placed of the substrate 11. By forming the groove 15, the underfill14 is suppressed from spreading to the optical layer 21 or theconnection pads 22.

In the case of the configuration described above, it is requested thatthe underfill 14 be reliably kept within a range surrounded by thegroove 15 and that a position where filling with the underfill 14 isstarted be provided, and therefore it is requested that the size of aframe configured by the groove 15 be formed so as to be greater than thesize of the electronic chip 13. Therefore, in a method for forming thegroove 15 so as to surround the electronic chip 13, it is difficult toincrease the area efficiency of the substrate 11, and the substrate 11is prevented from being reduced in size.

Furthermore, an amount of filling with the underfill 14 is limiteddepending on the size of the frame configured by the groove 15, andtherefore there is a possibility that filling with the underfill 14 willfail to be sufficiently performed depending on the size of the frame. Ina case where the underfill does not have a sufficient volume, a flowcharacteristic is degraded due to capillary action. In this case, a voidis generated in the underfill 14, and there is a possibility that theelectrodes 12 between the substrate 11 and the electronic chip 13 willnot be reliably sealed or protected.

Configuration Example of Solid-State Image Sensor According to thePresent Embodiment

FIG. 4 is a top view illustrating a configuration example of a substrateof a solid-state image sensor according to the present embodiment.However, in FIG. 4 , components that are common to components in theexample illustrated in FIG. 3 of the configuration of the solid-stateimage sensor are denoted by identical reference signs.

In FIG. 4 , electronic chips 13 such as logic circuits are placed abovea substrate 31 that includes Si or the like. Furthermore, an opticallayer 21 that includes a photodetector such as a photodiode (PD) isformed on a surface of the substrate 31.

A space between the electronic chip 13 and the substrate 31 is filledwith an underfill 14 that seals and protects electrodes 41 (FIG. 5 )that electrically connect the electronic chip 13 and the substrate 31.Furthermore, an inflow prevention unit 32 that prevents the underfill 14from flowing into the optical layer 21 is formed between a positionwhere the electronic chip 13 is placed of the substrate 31 and theoptical layer 21. Note that, as the inflow prevention unit 32, arecessed groove or a protruding wall may be formed in the substrate 31.

Moreover, connection pads 22 that are connected to a wire or the likethat transmits various signals are formed in the substrate 31.Furthermore, an inflow prevention unit 33 that prevents the underfill 14from flowing into the connection pad 22 is formed around the connectionpad 22 of the substrate 31.

Note that, as the inflow prevention unit 33, a recessed groove or aprotruding wall may be formed in the substrate 31.

Furthermore, the inflow prevention unit 33 may have a multiple structuresuch as a double or more structure rather than a single structure.

FIG. 5 is a sectional view in a case where the inflow prevention units32 and 33 are recessed grooves. An inclination angle θ of the recessedgroove with respect to a surface of the substrate 31 is assumed to rangefrom 60° to 90°. By setting the inclination angle θ to a steep angle of60° to 90°, the inflow of the underfill 14 can be stopped on an uppersurface of the groove due to the balance of a friction force between thesubstrate 31 and the underfill 14 and the surface tension of theunderfill 14. The depth and width of the groove are formed in such a waythat a ratio of the depth to the width (depth/width) falls in a range of0.5 to 16000.

FIG. 6 is a sectional view in a case where the inflow prevention units32 and 33 are protruding walls.

Note that one of the inflow prevention units 32 and 33 may be formed tobe a recessed groove and the other may be formed to be a protrudingwall.

Comparison of Configuration

In the configurations illustrated in FIGS. 1 to 3 of the solid-stateimage sensor, outflow is prevented by surrounding the underfill 14 byusing the groove 15 having a frame shape. In contrast, in the substrate31 of the solid-state image sensor according to the present embodiment,the inflow prevention units 32 and 33 are provided between a region tobe filled with the underfill 14 (in the case of FIG. 4 , a portion belowthe electronic chip 13) and a section that the underfill 14 is notdesired to flow into (in the case of FIG. 4 , the optical layer 21 andthe connection pads 22). With this arrangement, the underfill 14 isprevented from flowing into the section that the underfill 14 is notdesired to flow into.

By employing the configuration described above, the groove 15 having aframe shape for which a size is larger than the size of the electronicchip 13, as in the configurations illustrated in FIGS. 1 to 3 of thesolid-state image sensor, does not need to be formed. Therefore, forexample, the optical layer 21 in the substrate 31 and the electronicchip 13 can be arranged in such a way that a distance between theoptical layer 21 and the electronic chip 13 is shorter than distances inthe configurations illustrated in FIGS. 1 to 3 of the solid-state imagesensor. Thus, the area efficiency of the substrate 31 can be increased,and the size of the substrate 31 can be reduced.

Furthermore, the groove 15 having a frame shape is not formed.Therefore, the underfill 14 does not need to be kept inside a frame,filling with the underfill 14 having a sufficient amount can beperformed, and a void is suppressed from being generated in theunderfill 14. Thus, the electrodes 41 between the substrate 31 and theelectronic chip 13 can be reliably sealed and protected.

Note that the present technology is not only applicable to a substratethat configures a solid-state image sensor, but is also applicable to asubstrate that configures a general electronic apparatus.

However, only in an optical device such as a solid-state image sensor,the underfill 14 flows to the vicinity of pixels of the optical layer21, and image deterioration such as a flare or a ghost may occurdepending on a material that forms the optical layer 21. As acountermeasure against this, a method for reducing such a risk byselecting a material, making a coating material multilayered, or thelike may be applied. For example, an underfill may be used in a firstlayer, and a light shielding material or the like may only be used in aportion near the pixels of a second layer.

First Variation

In the configuration example illustrated in FIG. 4 , the inflowprevention unit 33 is formed so as to surround each of the connectionpads 22.

FIG. 7 is a top view illustrating a configuration example (a firstvariation) in which the inflow prevention unit 33 is formed so as tosurround a plurality of connection pads 22. In other words, in FIG. 7 ,an inflow prevention unit 331 that surrounds two connection pads 22 andan inflow prevention unit 332 that surrounds five connection pads 22 areformed.

In the case of this drawing, the groove 15 having a frame shape does notneed to be formed. Therefore, the area efficiency of a substrate 51 canbe increased, and the size of the substrate 51 can be reduced.Furthermore, the electrodes 41 between the substrate 51 and theelectronic chip 13 can be reliably sealed and protected.

Moreover, the underfill 14 can be suppressed from flowing into each ofthe connection pads 22.

Second Variation

FIG. 8 is a top view illustrating a configuration example (a secondvariation) in which a plurality of electronic chips 13 is placed above asubstrate 61 and a space between the plurality of electronic chips 13and the substrate 61 is integrally filled with the underfill 14. Inother words, in FIG. 8 , a space between three electronic chips 13-1 to13-3 and the substrate 61 is integrally filled with the underfill 14.

In the case of this drawing, each of the electronic chips 13 does notneed to be surrounded by the groove 15 having a frame shape. Therefore,the area efficiency of the substrate 61 can be increased, and the sizeof the substrate 61 can be reduced. Furthermore, the electrodes 41between the substrate 61 and each of the electronic chips 13 can bereliably sealed and protected.

Third Variation

FIG. 9 is a sectional view illustrating the case a configuration example(a third configuration example) in which a plurality of substrates 71 isstacked.

In other words, in FIG. 9 , substrates 71-1 and 71-2 are stacked viarelay solder balls 72, substrates 71-2 and 71-3 are stacked via therelay solder balls 72, the electronic chip 13 is placed above each ofthe substrates 71, and a space between the electronic chip 13 and thesubstrate 71 is filled with the underfill 14. Furthermore, the inflowprevention unit 32 is formed between a region to be filled with theunderfill 14 of each of the substrates 71 (a portion below theelectronic chip 13) and a section that the underfill 14 is not desiredto flow into (in the case of FIG. 9 , a surface component 73 and therelay solder balls 72).

In the case of this drawing, effects that are similar to effects in theconfiguration examples or variations described above can be achieved.

First Configuration Example of Structure Between Underfill and OpticalLayer

A first configuration example of a structure between the underfill 14and the optical layer 21 is described with reference to FIGS. 10A and10B.

FIG. 10A illustrates a top view in which a portion between the underfill14 and the optical layer 21 has been enlarged, and FIG. 10B illustratesa sectional view that corresponds to FIG. 10A.

For example, as described with reference to FIG. 4 , the inflowprevention unit 32 that prevents the underfill 14 from flowing into theoptical layer 21 is formed between the underfill 14 and the opticallayer 21. Note that a not-illustrated black-color filter may be stackedon a surface of the underfill 14 in order to suppress the surfacereflection of the underfill 14, and the black-color filter may bestacked in all of the configuration examples described below.

As described above, the inflow prevention unit 32 can have aconfiguration formed by a recessed groove (FIG. 5 ) or a protruding wall(FIG. 6 ), or a multiple structure including two or more recessedgrooves or protruding walls can be employed.

The inflow prevention unit 32 a illustrated in FIGS. 10A and 10B has aconfiguration in which five recessed groove portions 81-1 to 81-5 areformed. Furthermore, in the example illustrated in FIGS. 10A and 10B,the recessed groove portions 81-1 and 81-2 are covered with theunderfill 14. In other words, the underfill 14 enters the recessedgroove portions 81-1 and 81-2, and this prevents the underfill 14 fromflowing into the optical layer 21.

Then, it is desirable that the inflow prevention unit 32 a be formed insuch a way that an interval at which each of a plurality of recessedgroove portions 81 is arranged is a non-identical pitch, in order tosuppress an influence of reflected light and interference light on aportion that is not covered with the underfill 14.

For example, as illustrated, the plurality of recessed groove portions81 is arranged at a non-identical pitch in such a way that an intervalbetween the recessed groove portions 81 is reduced in a direction fromthe underfill 14 to the optical layer 21. Note that the plurality ofrecessed groove portions 81 may be arranged at a non-identical pitch atwhich the interval between the plurality of recessed groove portions 81increases in a direction from the underfill 14 to the optical layer 21or at a non-identical pitch at which the interval between the pluralityof recessed groove portions 81 is set at random.

Moreover, regarding the size of the inflow prevention unit 32 a, it ispreferable that processing be performed in such a way that the width ofthe recessed groove portion 81 and the interval (the pitch) between therecessed groove portions 81 range from λ/8 to 30λ with respect to acenter wavelength λ of incident light that enters the optical layer 21.For example, processing is performed in such a way that the width of therecessed groove portion 81 and the interval between the recessed grooveportions 81 range from 70 nm to 16,500 nm with respect to a centerwavelength of 550 nm. Specifically, each of the widths of the recessedgroove portions 81-1 to 81-5 is processed to be 3,000 nm, an intervalbetween the recessed groove portions 81-1 and 81-2 is processed to be10,000 nm, an interval between the recessed groove portions 81-2 and81-3 is processed to be 7,000 nm, an interval between the recessedgroove portions 81-3 and 81-4 is processed to be 5,000 nm, and aninterval between the recessed groove portions 81-4 and 81-5 is processedto be 3,000 nm.

Furthermore, a flat region 82 on which processing such as a groove isnot performed is provided between the inflow prevention unit 32 a andthe optical layer 21. Then, it is preferable that a width d of the flatregion 82 and in other words, a distance from the inflow prevention unit32 a to the optical layer 21 be formed to range from λ/8 to 30λ withrespect to a center wavelength λ of incident light that enters theoptical layer 21, in order to suppress an influence of reflected lightor interference light. For example, it is preferable that the width d ofthe flat region 82 range from 70 nm to 16,500 nm with respect to acenter wavelength of 550 nm.

As described above, a structure, in which the inflow prevention unit 32a includes the plurality of recessed groove portions 81 arranged at anon-identical pitch as well as the width d of the flat region 82 fallsin a prescribed range, is employed between the underfill 14 and theoptical layer 21. By doing this, the underfill 14 can be prevented fromflowing into the optical layer 21, an influence of reflected light andinterference light can be suppressed between the underfill 14 and theoptical layer 21, and the deterioration of image quality due to, forexample, a flare, a ghost, or the like can be avoided.

Second Configuration Example of Structure Between Underfill and OpticalLayer

A second configuration example of the structure between the underfill 14and the optical layer 21 is described with reference to FIGS. 11A and11B. Note that, in the structure illustrated in FIGS. 11A and 11B,portions that are common to portions in the structure illustrated inFIGS. 10A and 10B are denoted by identical reference signs, and thedetailed description thereof is omitted.

FIG. 11A illustrates a top view in which a portion between the underfill14 and the optical layer 21 has been enlarged, and FIG. 11B illustratesa sectional view that corresponds to FIG. 11A.

The inflow prevention unit 32 b illustrated in FIGS. 11A and 11B has aconfiguration in which five recessed groove portions 81-1 to 81-5 areformed. Furthermore, in the example illustrated in FIGS. 11A and 11B,the recessed groove portions 81-1 and 81-2 are covered with theunderfill 14. In other words, the underfill 14 enters the recessedgroove portions 81-1 and 81-2, and this prevents the underfill 14 fromflowing into the optical layer 21.

Then, it is desirable that the inflow prevention unit 32 b be formed insuch a way that a plurality of recessed groove portions 81 has widthsthat are not identical to each other and an interval at which each ofthe plurality of recessed groove portions 81 is arranged is anon-identical pitch, in order to suppress an influence of reflectedlight and interference light on a portion that is not covered with theunderfill 14. In other words, the inflow prevention unit 32 b isconfigured in such a way that the widths of the plurality of recessedgroove portions 81 are different from each other and intervals betweenthe plurality of recessed groove portions 81 are different from eachother.

For example, as illustrated, the plurality of recessed groove portions81 having non-identical widths is arranged at a non-identical pitch, insuch a way that the width of the recessed groove portion 81 is reducedand an interval between the recessed groove portions 81 is reduced in adirection from the underfill 14 to the optical layer 21. Note that theplurality of recessed groove portions 81 may be arranged at anon-identical pitch at which the width of the recessed groove portion 81increases and the interval between the recessed groove portions 81increases in a direction from the underfill 14 to the optical layer 21or at a non-identical pitch at which the widths of the recessed grooveportions 81 and the intervals between the recessed groove portions 81are set at random.

Moreover, regarding the size of the inflow prevention unit 32 b, it ispreferable that processing be performed in such a way that the width ofthe recessed groove portion 81 and the interval (the pitch) between therecessed groove portions 81 range from λ/8 to 30λ with respect to acenter wavelength λ of incident light that enters the optical layer 21.For example, processing is performed in such a way that the width of therecessed groove portion 81 and the interval between the recessed grooveportions 81 range from 70 nm to 16,500 nm with respect to a centerwavelength of 550 nm. Specifically, the width of the recessed grooveportion 81-1 is processed to be 10,000 nm, the width of the recessedgroove portion 81-2 is processed to be 7,000 nm, the width of therecessed groove portion 81-3 is processed to be 5,000 nm, the width ofthe recessed groove portion 81-4 is processed to be 3,000 nm, and thewidth of the recessed groove portion 81-5 is processed to be 1,000 nm.Furthermore, an interval between the recessed groove portions 81-1 and81-2 is processed to be 10,000 nm, an interval between the recessedgroove portions 81-2 and 81-3 is processed to be 7,000 nm, an intervalbetween the recessed groove portions 81-3 and 81-4 is processed to be5,000 nm, and an interval between the recessed groove portions 81-4 and81-5 is processed to be 3,000 nm.

Furthermore, it is preferable that a width d of a flat region 82 that isprovided between the inflow prevention unit 32 b and the optical layer21 be formed to range from λ/8 to 30λ with respect to a centerwavelength λ of incident light that enters the optical layer 21,similarly to the description given above with reference to FIGS. 10A and10B.

As described above, a structure, in which the inflow prevention unit 32b includes the plurality of recessed groove portions 81 havingnon-identical widths and arranged at a non-identical pitch and the widthd of the flat region 82 falls in a prescribed range, is employed betweenthe underfill 14 and the optical layer 21. By doing this, the underfill14 can be prevented from flowing into the optical layer 21, an influenceof reflected light and interference light can be suppressed between theunderfill 14 and the optical layer 21, and the deterioration of imagequality due to, for example, a flare, a ghost, or the like can beavoided.

Third and Fourth Configuration Examples of Structure Between Underfilland Optical Layer

Third and fourth configuration examples of the structure between theunderfill 14 and the optical layer 21 are described with reference toFIGS. 12 and 13 . Note that, in the structures illustrated in FIGS. 12and 13 , portions that are common to portions in the structureillustrated in FIGS. 10A and 10B are denoted by identical referencesigns, and the detailed description thereof is omitted.

FIG. 12 illustrates a top view in the third configuration example of thestructure between the underfill 14 and the optical layer 21, and FIG. 13illustrates a top view in the fourth configuration example of thestructure between the underfill 14 and the optical layer 21.

The inflow prevention unit 32 c illustrated in FIG. 12 has aconfiguration in which a plurality of circular recesses 91 is formed ina discontinuous arrangement. Furthermore, in the example illustrated inFIG. 12 , some of the plurality of circular recesses 91 are covered withthe underfill 14. In other words, the underfill 14 enters the some ofthe plurality of circular recesses 91, and this prevents the underfill14 from flowing into the optical layer 21.

Then, it is desirable that the inflow prevention unit 32 c be processedin such a way that the plurality of circular recesses 91 has sizes thatare not identical to each other and are arranged at a non-identicalpitch, in order to suppress an influence of reflected light andinterference light on a portion that is not covered with the underfill14. In other words, the inflow prevention unit 32 c is processed in sucha way that the diameters a of the plurality of circular recesses 91 aredifferent from each other and intervals b between the plurality ofcircular recesses 91 are different from each other, and is processed insuch a way that the respective diameters a and the respective intervalsb are set at random.

Moreover, regarding the size of the inflow prevention unit 32 c, it ispreferable that processing be performed in such a way that the diametera of the circular recess 91 and the interval b between the circularrecesses 91 range from λ/8 to 30λ with respect to a center wavelength λof incident light that enters the optical layer 21. For example,processing is performed in such a way that the diameter a of thecircular recess 91 and the interval b between the circular recesses 91range from 70 nm to 16,500 nm with respect to a center wavelength of 550nm. Specifically, the diameters a of the plurality of circular recesses91 are processed at random to be 10,000 nm, 7,000 nm, 5,000 nm, 3,000nm, and 1,000 nm, respectively, and the intervals b between the circularrecesses 91 are processed at random to be 5,000 nm, 3,000 nm, and 1,000nm, respectively.

Furthermore, it is preferable that a width d of a flat region 82 that isprovided between the inflow prevention unit 32 c and the optical layer21 be formed to range from λ/8 to 30λ with respect to a centerwavelength λ of incident light that enters the optical layer 21,similarly to the description given above with reference to FIGS. 10A and10B.

Note that the inflow prevention unit 32 d illustrated in FIG. 13 has aconfiguration in which a plurality of rectangular recesses 92 are formedat random similarly to the circular recesses 91 of the inflow preventionunit 32 c illustrated in FIG. 12 , and has a similar configuration inthe other respects. Note that the inflow prevention unit 32 may have aconfiguration in which recesses having a shape that is not circular orrectangular are arranged at random.

Furthermore, it is desirable that a configuration be always employed inwhich some of the circular recesses 91 that are formed in the inflowprevention unit 32 c or some of the rectangular recesses 92 that areformed in the inflow prevention unit 32 d appear between the underfill14 and the optical layer 21, rather than a configuration in which theentire portion between the underfill 14 and the optical layer 21 isflat.

As described above, between the underfill 14 and the optical layer 21, astructure is employed in which the inflow prevention unit 32 c includesthe circular recesses 91 that are arranged at random, or the inflowprevention unit 32 d includes the rectangular recesses 92, and the widthd of the flat region 82 falls in a prescribed range. By doing this, theunderfill 14 can be prevented from flowing into the optical layer 21, aninfluence of reflected light and interference light can be suppressedbetween the underfill 14 and the optical layer 21, and the deteriorationof image quality due to, for example, a flare, a ghost, or the like canbe avoided.

Application Example

The present technology may be implemented, for example, as an apparatusthat is installed on any type of moving body such as a vehicle, anelectric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, apersonal mobility, an airplane, a drone, a ship, a robot, a constructionmachine, or an agricultural machine (a tractor).

FIG. 14 is a block diagram illustrating a rough configuration example ofa vehicle control system 7000 that is an example of a moving bodycontrol system to which a technology according to the present disclosuremay be applied. The vehicle control system 7000 includes a plurality ofelectronic control units that are connected via a communication network7010. In the example illustrated in FIG. 14 , the vehicle control system7000 includes a driving system control unit 7100, a body system controlunit 7200, a battery control unit 7300, an outside-vehicle informationdetection unit 7400, an in-vehicle information detection unit 7500, andan integrated control unit 7600. The communication network 7010 thatconnect these plurality of control units may be an in-vehiclecommunication network in compliance with an arbitrary standard such as acontroller area network (CAN), a local interconnect network (LIN), alocal area network (LAN), or a FlexRay (registered trademark), forexample.

Each of the control units includes a microcomputer that performsarithmetic processing in accordance with various programs, a storagethat stores a program that is executed by the microcomputer, a parameterused in various arithmetic operations, or the like, and a drivingcircuit that drives various apparatuses to be controlled. Each of thecontrol units includes a network I/F that performs communication withanother control unit via the communication network 7010, and alsoincludes a communication I/F that performs communication with anapparatus, a sensor, or the like inside or outside a vehicle throughwired communication or wireless communication. In FIG. 14 , amicrocomputer 7610, a general-purpose communication I/F 7620, adedicated communication I/F 7630, a positioning unit 7640, a beaconreceiver 7650, an in-vehicle equipment I/F 7660, a sound or image outputunit 7670, an in-vehicle network I/F 7680, and a storage 7690 areillustrated as a functional configuration of the integrated control unit7600. The other control units similarly include the microcomputer, thecommunication I/F, the storage, and the like.

The driving system control unit 7100 controls an operation of anapparatus that relates to a driving system of a vehicle in accordancewith various programs. For example, the driving system control unit 7100functions as a control apparatus of a driving force generation apparatusthat generates a driving force of a vehicle, such as an internalcombustion engine or a driving motor, a driving force transmissionmechanism that transmits the driving force to wheels, a steeringmechanism that adjusts a steering angle of the vehicle, a brakingapparatus that generates a braking force of the vehicle, and the like.The driving system control unit 7100 may have a function of a controlapparatus of an antilock brake system (ABS), electronic stabilitycontrol (ESC), or the like.

A vehicle state detector 7110 is connected to the driving system controlunit 7100. The vehicle state detector 7110 includes, for example, atleast one of a gyro sensor that detects the angular velocity of a shaftrotary motion of a vehicle body, an acceleration sensor that detects theacceleration of a vehicle, or a sensor that detects an amount of anoperation performed on an accelerator pedal, an amount of an operationperformed on a brake pedal, a steering angle of a steering wheel, enginespeed, the rotational speed of a wheel, or the like. The driving systemcontrol unit 7100 performs arithmetic processing using a signal inputfrom the vehicle state detector 7110, and controls the internalcombustion engine, the driving motor, an electric power steeringapparatus, a brake apparatus, or the like.

The body system control unit 7200 controls the operations of variousapparatuses equipped in the vehicle body in accordance with variousprograms. For example, the body system control unit 7200 functions as acontrol apparatus of a keyless entry system, a smart key system, a powerwindow apparatus, or various lamps such as a headlamp, a back lamp, abrake lamp, a turn signal, or a fog lamp. In this case, radio wavestransmitted from a portable machine that is substituted for a key orsignals of various switches may be input to the body system control unit7200. The body system control unit 7200 receives an input of these radiowaves or signals, and controls a door locking apparatus, the powerwindow apparatus, a lamp, or the like of the vehicle.

The battery control unit 7300 controls a secondary battery 7310 servingas a power supply source of the driving motor in accordance with variousprograms. For example, information relating to battery temperature, abattery output voltage, the residual capacity of a battery, or the likeis input to the battery control unit 7300 from a battery apparatusincluding the secondary battery 7310. The battery control unit 7300performs arithmetic processing using these signals, and performstemperature regulating control on the secondary battery 7310 or performscontrol on a cooling apparatus or the like that is included in thebattery apparatus.

The outside-vehicle information detection unit 7400 detects informationrelating to the outside of a vehicle in which the vehicle control system7000 is installed. For example, at least one of an imaging unit 7410 oran outside-vehicle information detector 7420 is connected to theoutside-vehicle information detection unit 7400. The imaging unit 7410includes at least one of a time-of-flight (ToF) camera, a stereo camera,a monocular camera, an infrared camera, or another camera. Theoutside-vehicle information detector 7420 includes, for example, atleast one of an environmental sensor that detects current weather oratmospheric phenomena or a surrounding information detection sensor thatdetects another vehicle, an obstacle, a pedestrian, or the like aroundthe vehicle in which the vehicle control system 7000 is installed.

The environmental sensor may be, for example, at least one of a raindropsensor that detects rainy weather, a fog sensor that detects fog, asunshine sensor that detects a level of sunshine, or a snow sensor thatdetects snowfall. The surrounding information detection sensor may be atleast one of an ultrasonic sensor, a radar apparatus, or a lightdetection and ranging or laser imaging detection and ranging (LIDAR)apparatus. The imaging unit 7410 and the outside-vehicle informationdetector 7420 described above may be included as independent sensors orapparatuses, or may be included as an apparatus in which a plurality ofsensors or apparatuses is integrated.

Here, FIG. 15 illustrates an example of the installation position of theimaging unit 7410 and the outside-vehicle information detector 7420.Imaging units 7910, 7912, 7914, 7916, and 7918 are provided, forexample, in at least one position of a front nose, a side-view mirror, arear bumper, a back door, or an upper portion of a windshield in avehicle cabin of a vehicle 7900. The imaging unit 7910 included in thefront nose and the imaging unit 7918 included in the upper portion ofthe windshield in the vehicle cabin principally obtain an image of afront side of the vehicle 7900. The imaging units 7912 and 7914 includedin the side-view mirrors principally obtain an image of a side of thevehicle 7900. The imaging unit 7916 included in the rear bumper or theback door principally obtains an image of a rear side of the vehicle7900. The imaging unit 7918 included in the upper portion of thewindshield in the vehicle cabin is principally used to detect apreceding vehicle, or a pedestrian, an obstacle, a traffic light, atraffic sign, a traffic lane, or the like.

Note that FIG. 15 illustrates an example of a photographing range ofeach of the imaging units 7910, 7912, 7914, and 7916. An imaging range aindicates an imaging range of the imaging unit 7910 provided in thefront nose, imaging ranges b and c respectively indicate imaging rangesof the imaging units 7912 and 7914 provided in the side-view mirrors,and an imaging range d indicates an imaging range of the imaging unit7916 provided in the rear bumper or the back door. For example, anoverhead image in which the vehicle 7900 is viewed from the above isobtained by superimposing pieces of image data that have been capturedby the imaging units 7910, 7912, 7914, and 7916 onto each other.

Outside-vehicle information detectors 7920, 7922, 7924, 7926, 7928, and7930 that are provided in a front portion, a rear portion, sides,corners, and the upper portion of the windshield in vehicle cabin of thevehicle 7900 may be, for example, ultrasonic sensors or radarapparatuses. The outside-vehicle information detectors 7920, 7926, and7930 that are provided in the front nose, the rear bumper, the backdoor, and the upper portion of the windshield in the vehicle cabin ofthe vehicle 7900 may be, for example, LIDAR apparatuses. Theseoutside-vehicle information detectors 7920 to 7930 are principally usedto detect a preceding vehicle, a pedestrian, an obstacle, or the like.

Return to the description of FIG. 14 . The outside-vehicle informationdetection unit 7400 causes the imaging unit 7410 to capture an image ofthe outside of the vehicle, and receives captured image data.Furthermore, the outside-vehicle information detection unit 7400receives detection information from the connected outside-vehicleinformation detector 7420. In a case where the outside-vehicleinformation detector 7420 is an ultrasonic sensor, a radar apparatus, ora LIDAR apparatus, the outside-vehicle information detection unit 7400causes ultrasonic waves, electromagnetic waves, or the like to betransmitted, and receives information relating to received reflectedwaves. The outside-vehicle information detection unit 7400 may performobject detection processing or distance detection processing on aperson, a car, an obstacle, a traffic sign, characters on a roadsurface, or the like on the basis of the received information. Theoutside-vehicle information detection unit 7400 may perform environmentrecognition processing for recognizing rainfall, fog, a road surfacecondition, or the like on the basis of the received information. Theoutside-vehicle information detection unit 7400 may calculate a distanceto an object outside the vehicle on the basis of the receivedinformation.

Furthermore, the outside-vehicle information detection unit 7400 mayperform image recognition processing or distance detection processingfor recognizing a person, a car, an obstacle, a traffic sign, characterson a road surface, or the like on the basis of the received image data.The outside-vehicle information detection unit 7400 may performprocessing such as distortion correction or alignment on the receivedimage data and may combine pieces of image data captured by the imagingunits 7410 different from each other so as to generate an overhead imageor a panoramic image. The outside-vehicle information detection unit7400 may perform viewpoint conversion processing using the image datacaptured by the imaging units 7410 different from each other.

The in-vehicle information detection unit 7500 detects in-vehicleinformation. A driver state detector 7510 that detects a state of adriver is connected, for example, to the in-vehicle informationdetection unit 7500. The driver state detector 7510 may include a camerathat captures an image of the driver, a biosensor that detectsbiological information relating to the driver, a microphone thatcollects sound in the vehicle cabin, or the like. The biosensor isprovided, for example, on a seat surface, a steering wheel, or the like,and detects biological information relating to a passenger who is seatedon a seat or a driver who is holding the steering wheel. The in-vehicleinformation detection unit 7500 may calculate a fatigue degree or aconcentration degree of the driver or may determine whether or not thedriver is dozing on the basis of detection information input from thedriver state detector 7510. The in-vehicle information detection unit7500 may perform processing, such as noise canceling processing, oncollected sound signal.

The integrated control unit 7600 controls the entire operation insidethe vehicle control system 7000 in accordance with various programs. Aninput unit 7800 is connected to the integrated control unit 7600. Theinput unit 7800 is realized, for example, by an apparatus, such as atouch panel, a button, a microphone, a switch, or a lever, on which thepassenger may perform an input operation. Data obtained by performingsound recognition on sound that has been input from the microphone maybe input to the integrated control unit 7600. The input unit 7800 maybe, for example, a remote controller that uses infrared rays or otherradio waves, or external connection equipment, such as a portabletelephone or a personal digital assistant (PDA), that corresponds to anoperation performed on the vehicle control system 7000. The input unit7800 may be, for example, a camera, and in this case, the passenger caninput information by using a gesture. Alternatively, data obtained bydetecting a movement of a wearable apparatus attached to the passengermay be input. Moreover, the input unit 7800 may include, for example, aninput control circuit or the like that generates an input signal on thebasis of the information described above that has been input by thepassenger or the like by using the input unit 7800 and outputs the inputsignal to the integrated control unit 7600. The passenger or the likeinputs various types of data to the vehicle control system 7000 orissues, to the vehicle control system 7000, an instruction relating to aprocessing operation, by operating this input unit 7800.

The storage 7690 may include a read only memory (ROM) that storesvarious programs executed by the microcomputer and a random accessmemory (RAM) that stores various parameters, arithmetic results, sensorvalues, or the like. Furthermore, the storage 7690 may be realized by amagnetic storage device such as a hard disc drive (HDD), a semiconductorstorage device, an optical storage device, a magneto-optical storagedevice, or the like.

The general-purpose communication I/F 7620 is a general-purposecommunication I/F that mediates communication with various pieces ofequipment that are present in an external environment 7750. Thegeneral-purpose communication I/F 7620 may implement a cellularcommunication protocol such as global system of mobile communications(GSM), WiMAX, long term evolution (LTE), or LTE-advanced (LTE-A), oranother wireless communication protocol such as a wireless LAN (alsoreferred to as Wi-Fi (registered trademark)) or Bluetooth (registeredtrademark). The general-purpose communication I/F 7620 may performconnection to equipment (for example, an application server or a controlserver) that is present on an external network (for example, theInternet, a cloud network, or a company-specific network), for example,via a base station or an access point. Furthermore, the general-purposecommunication I/F 7620 may perform connection to a terminal that ispresent near the vehicle (for example, a terminal of the driver, apedestrian, or a store, or a machine type communication (MTC) terminal)by using, for example, a peer to peer (P2P) technology.

The dedicated communication I/F 7630 is a communication I/F thatsupports a communication protocol formulated for the purpose of use in avehicle. The dedicated communication I/F 7630 may implement a standardprotocol such as wireless access in vehicle environment (WAVE), which isa combination of IEEE 802.11p of a lower-order layer and IEEE 1609 of anupper-order layer, dedicated short range communications (DSRC), or acellular communication protocol. The dedicated communication I/F 7630typically performs V2X communication, which is a concept including oneor more of vehicle to vehicle communication, vehicle to infrastructurecommunication, vehicle to home communication, and vehicle to pedestriancommunication.

The positioning unit 7640 receives, for example, a global navigationsatellite system (GNSS) signal from a GNSS satellite (for example, aglobal positioning system (GPS) signal from a GPS satellite), performspositioning, and generates position information including the latitude,longitude, and altitude of a vehicle. Note that the positioning unit7640 may specify a current position by exchanging signals with awireless access point, or may obtain the position information from aterminal, such as a portable telephone, a PHS, or a smartphone, that hasa positioning function.

The beacon receiver 7650 receives radio waves or electromagnetic wavesthat have been transmitted from, for example, a wireless station that isprovided on a road, or the like, and obtains information relating to acurrent position, a traffic jam, road closure, a required time, or thelike. Note that a function of the beacon receiver 7650 may be includedin the dedicated communication I/F 7630 described above.

The in-vehicle equipment I/F 7660 is a communication interface thatmediates connection between the microcomputer 7610 and various pieces ofin-vehicle equipment 7760 that are present in a vehicle. The in-vehicleequipment I/F 7660 may establish wireless connection by using a wirelesscommunication protocol such as a wireless LAN, Bluetooth (registeredtrademark), near field communication (NFC), or wireless USB (WUSB).Furthermore, the in-vehicle equipment I/F 7660 may establish wiredconnection such as a universal serial bus (USB), a high-definitionmultimedia interface (HDMI), or a mobile high-definition link (MHL) viaa not-illustrated connection terminal (and a cable if necessary). Thein-vehicle equipment 7760 may include, for example, at least one ofmobile equipment or wearable equipment that the passenger has orinformation equipment that is carried in or attached to the vehicle.Furthermore, the in-vehicle equipment 7760 may include a navigationapparatus that searches for a route to an arbitrary destination. Thein-vehicle equipment I/F 7660 exchanges control signals or data signalswith these pieces of in-vehicle equipment 7760.

The in-vehicle network I/F 7680 is an interface that mediatescommunication between the microcomputer 7610 and the communicationnetwork 7010. The in-vehicle network I/F 7680 transmits and receives asignal or the like in accordance with a prescribed protocol supported bythe communication network 7010.

The microcomputer 7610 of the integrated control unit 7600 controls thevehicle control system 7000 in accordance with various programs on thebasis of information that has been obtained via at least one of thegeneral-purpose communication I/F 7620, the dedicated communication I/F7630, the positioning unit 7640, the beacon receiver 7650, thein-vehicle equipment I/F 7660, or the in-vehicle network I/F 7680. Forexample, the microcomputer 7610 may calculate a control target value ofthe driving force generator, the steering mechanism, or the brakingapparatus on the basis of obtained in-vehicle or outside-vehicleinformation, and may output a control command to the driving systemcontrol unit 7100. For example, the microcomputer 7610 may performcooperative control aiming at implementing a function of an advanceddriver assistance system (ADAS) including vehicle collision avoidance orimpact mitigation, following traveling based on a distance betweenvehicles, vehicle speed maintaining traveling, vehicle collisionwarning, vehicle lane departure warning, or the like. Furthermore, themicrocomputer 7610 may cooperative control aiming at automatic drivingor the like for autonomously traveling independently of a driver’soperation by controlling the driving force generator, the steeringmechanism, the braking apparatus, or the like on the basis of obtainedinformation relating to the periphery of the vehicle.

The microcomputer 7610 may generate three-dimensional distanceinformation between the vehicle and a peripheral object such as astructure or a person on the basis of information obtained via at leastone of the general-purpose communication I/F 7620, the dedicatedcommunication I/F 7630, the positioning unit 7640, the beacon receiver7650, the in-vehicle equipment I/F 7660, or the in-vehicle network I/F7680, and may generate local map information including peripheralinformation of a current position of the vehicle. Furthermore, themicrocomputer 7610 may predict danger such as vehicle collision, theapproach of a pedestrian or the like, or entry to a closed road on thebasis of the obtained information, and may generate a warning signal.The warning signal may be, for example, a signal that causes warningsound to be emitted or causes a warning lamp to glow.

The sound or image output unit 7670 transmits an output signal of atleast one of sound or an image to an output apparatus that can visuallyor aurally report information to a passenger of a vehicle or the outsideof the vehicle. In the example of FIG. 13 , an audio speaker 7710, adisplay 7720, and an instrument panel 7730 are illustrated as the outputapparatus. The display 7720 may include, for example, at least one of anon-board display or a head-up display. The display 7720 may have anaugmented reality (AR) display function. The output apparatus may be anapparatus other than the apparatuses described above, e.g. a headphone,a wearable device such as an eyeglasses type display that is attached toa passenger, a projector, a lamp, or the like. In a case where theoutput apparatus is a display apparatus, the display apparatus visuallydisplays a result obtained in various types of processing performed bythe microcomputer 7610 or information received from another control unitin various forms such as text, an image, a table, or a graph.Furthermore, in a case where the output apparatus is a sound outputapparatus, the sound output apparatus converts a reproduced audio signalincluding sound data, acoustic data, or the like into an analog signal,and aurally outputs the analog signal.

Note that, in the example illustrated in FIG. 14 , at least two controlunits that are connected via the communication network 7010 may beintegrated as a single control unit. Alternatively, an individualcontrol unit may include a plurality of control units. Moreover, thevehicle control system 7000 may include another not-illustrated controlunit. Furthermore, in the description above, another control unit mayhave some or all of the functions of any control unit. That is,prescribed arithmetic processing may be performed by any control unit ifinformation is to be transmitted/received via the communication network7010. Similarly, a sensor or an apparatus that is connected to anycontrol unit may be connected to another control unit, and a pluralityof control units may mutually transmit/receive detection information viathe communication network 7010.

In the vehicle control system 7000 described above, the solid-stateimage sensor according to the present embodiment is applicable to theintegrated control unit 7600 of the application example illustrated inFIG. 14 .

Furthermore, at least some of the components of the solid-state imagesensor according to the present embodiment may be realized in a modulefor the integrated control unit 7600 illustrated in FIG. 14 (forexample, an integrated circuit module including a single die).Alternatively, the solid-state image sensor according to the presentembodiment may be implemented by a plurality of control units of thevehicle control system 7000 illustrated in FIG. 14 .

Note that embodiments according to the present technology are notlimited to the embodiment described above, and various changes can bemade without departing from the scope of the present technology.

-   The present technology can also employ the configuration described    below.

(1) An electronic substrate including:

-   an electronic chip that is placed above a substrate;-   an electrode that exists between the substrate and the electronic    chip and electrically connects the substrate and the electronic    chip;-   an underfill with which a space between the substrate and the    electronic chip is filled so that the electrode is sealed and    protected;-   a protection target to be protected from inflow of the underfill,    the protection target being formed on the substrate; and-   an underfill inflow prevention unit that is formed in the substrate    so as to surround an entirety or a portion of the protection target.

(2) The electronic substrate described in the above paragraph (1),

-   in which the underfill inflow prevention unit has a multiple    structure.

(3) The electronic substrate described in the above paragraph (1) or(2),

-   in which the underfill inflow prevention unit is a recessed groove.

(4) The electronic substrate described in the above paragraph (3),

-   in which the recessed groove has an inclination angle of 60 ° to 90    ° with respect to a surface of the substrate.

(5) The electronic substrate described in the above paragraph (3) or(4),

-   in which a depth/width of the recessed groove ranges from 0.5 to    16000.

(6) The electronic substrate described in the above paragraph (1) or(2),

-   in which the underfill inflow prevention unit is a protruding wall.

(7) The electronic substrate described in any one of the aboveparagraphs (1) to (6),

-   in which the protection target is a connection pad that is connected    to external equipment.

(8) The electronic substrate described in any one of the aboveparagraphs (1) to (7),

-   in which the protection target is a light-receiving layer,-   the electronic chip is a semiconductor chip including a functional    circuit, and-   the electronic substrate is a component of a solid-state image    sensor.

(9) The electronic substrate described in any one of the aboveparagraphs (1) to (8),

-   in which the underfill inflow prevention unit is formed in the    substrate so as to surround all or some of one or a plurality of the    protection targets.

(10) The electronic substrate described in the above paragraph (8),

-   in which a width of a flat portion provided between the underfill    and the light-receiving layer ranges from λ/8 to 30λ with respect to    a center wavelength λ of incident light that enters the    light-receiving layer.

(11) The electronic substrate described in the above paragraph (10),

-   in which the underfill inflow prevention unit includes a plurality    of recessed groove portions, and an interval at which each of the    plurality of recessed groove portions is a non-identical pitch.

(12) The electronic substrate described in the above paragraph (11),

-   in which an interval between the plurality of recessed groove    portions ranges from λ/8 to 30λ with respect to the center    wavelength λ of the incident light that enters the light-receiving    layer.

(13) The electronic substrate described in the above paragraph (11) or(12),

-   in which the plurality of recessed groove portions is formed to have    widths different from each other.

(14) The electronic substrate described in any one of the aboveparagraphs (11) to (13),

-   in which a width of each of the plurality of recessed groove    portions ranges from λ/8 to 30λ with respect to the center    wavelength λ of the incident light that enters the light-receiving    layer.

(15) An electronic apparatus in which an electronic substrate isemployed,

-   in which the electronic substrate includes:    -   an electronic chip that is placed above a substrate;    -   an electrode that exists between the substrate and the        electronic chip and electrically connects the substrate and the        electronic chip;    -   an underfill with which a space between the substrate and the        electronic chip is filled so that the electrode is sealed and        protected;    -   a protection target to be protected from inflow of the        underfill, the protection target being formed on the substrate;        and    -   an underfill inflow prevention unit that is formed in the        substrate so as to surround an entirety or a portion of the        protection target.

REFERENCE SIGNS LIST 11 Substrate 12 Electrode 13 Electronic chip 14Underfill 15 Groove 21 Optical layer 22 Connection pad 31 Substrate 32Inflow prevention unit 33 Inflow prevention unit 41 Electrode 71Substrate 72 Relay solder ball

What is claimed is:
 1. An electronic substrate, comprising: anelectronic chip above a substrate; an electrode between the substrateand the electronic chip, wherein the electrode electrically connects thesubstrate and the electronic chip; an underfill in a space between thesubstrate and the electronic chip to seal the electrode; a protectiontarget on the substrate; and a first inflow prevention unit configuredto prevent the underfill from flowing into the protection target,wherein the first inflow prevention unit includes a first recessedgroove that surrounds the protection target on all sides of theprotection target.
 2. The electronic substrate according to claim 1,further comprising an optical layer on a surface of the substrate. 3.The electronic substrate according to claim 2, further comprising asecond inflow prevention unit configured to prevent the underfill fromflowing into the optical layer, wherein the second inflow preventionunit is between the electronic chip and the optical layer.
 4. Theelectronic substrate according to claim 3, wherein the second inflowprevention unit includes one of a second recessed groove or a protrudingwall.
 5. The electronic substrate according to claim 3, wherein thesecond inflow prevention unit includes a plurality of second recessedgrooves, a shape of each of the plurality of second recessed grooves isone of circular or rectangular, and each of the plurality of secondrecessed grooves has a different size.
 6. The electronic substrateaccording to claim 1, wherein the first recessed groove has aninclination angle of 60° to 90° with respect to a surface of thesubstrate.
 7. The electronic substrate according to claim 1, wherein aratio of a depth to a width of the first recessed groove ranges from 0.5to
 16000. 8. The electronic substrate according to claim 1, wherein theprotection target is a connection pad connected to an externalequipment.
 9. The electronic substrate according to claim 1, furthercomprising a plurality of protection targets including the protectiontarget, wherein the first inflow prevention unit is in the substrate soas to surround the protection target.
 10. The electronic substrateaccording to claim 1, wherein the protection target is a light-receivinglayer, the electronic chip is a semiconductor chip including afunctional circuit, and the electronic substrate is a component of asolid-state image sensor.
 11. The electronic substrate according toclaim 10, wherein a width of a flat portion between the underfill andthe light-receiving layer ranges from λ/8 to 30λ with respect to acenter wavelength λ of incident light that enters the light-receivinglayer.
 12. The electronic substrate according to claim 11, wherein thefirst recessed groove includes a plurality of recessed groove portions,and an interval between each of the plurality of recessed grooveportions has a nonidentical pitch.
 13. The electronic substrateaccording to claim 12, wherein the interval between the plurality ofrecessed groove portions ranges from λ/8 to 30λ with respect to thecenter wavelength λ of the incident light that enters thelight-receiving layer.
 14. The electronic substrate according to claim12, wherein a width of a first recessed groove portion of the pluralityof recessed groove portions is different from a width of a secondrecessed groove portion of the plurality of recessed groove portions.15. The electronic substrate according to claim 12, wherein a width ofeach of the plurality of recessed groove portions ranges from λ/8 to 30λwith respect to the center wavelength λ of the incident light thatenters the light-receiving layer.
 16. The electronic substrate accordingto claim 1, wherein the protection target comprises a plurality ofconnection pads, and the first inflow prevention unit surrounds theplurality of connection pads.
 17. The electronic substrate according toclaim 1, wherein the protection target comprises a plurality ofconnection pads, the first inflow prevention unit further includes asecond recessed groove, the first recessed groove surrounds a firstnumber of connection pads of the plurality of connection pads, and thesecond recessed groove surrounds a second number of connection pads,greater than the first number of connection pads, of the plurality ofconnection pads.
 18. An electronic apparatus, comprising: an electronicsubstrate that comprises: an electronic chip above a substrate; anelectrode between the substrate and the electronic chip, wherein theelectrode electrically connects the substrate and the electronic chip;an underfill in a space between the substrate and the electronic chip toseal the electrode; a protection target on the substrate; and an inflowprevention unit configured to prevent the underfill from flowing intothe protection target, wherein the inflow prevention unit includes arecessed groove that surrounds the protection target on all sides of theprotection target.